The present invention relates to a digital data reproduction device which receives and decrypts encrypted digital data to reproduce the original digital data and more particularly to a reproduction device which prevents unauthorized copying of data.
This application is based on Japanese Patent Application No. 9-107541, filed Apr. 24, 1997, the content of which is incorporated herein by reference.
In recent years, networking of digital devices has advanced as multimedia applications have evolved. That is, the transmission of digital data is increasingly being made not only between general-purpose computers, such as personal computers, but also between dedicated AV units, such as audio-visual equipment, or between a dedicated AV unit and a general-purpose computer. As one of digital interface standards that allow the transmission of digital data between a computer and a dedicated AV unit, an IEEE standard, IEEE 1394, was established recently.
However, the use of this standard to receive and decrypt encrypted multimedia data with a general-purpose computer causes a problem that unauthorized copies of digital data can be produced readily. The unauthorized copy, which is produced by digital processing, suffers from no degradation in picture quality and sound quality, allowing high picture quality duplications (so-called pirated editions) and leading to an infringement of copyrights. The dedicated AV unit is constructed such that multimedia data obtained by decrypting encrypted data cannot be taken out until it is converted by a digital-to-analog converter into analog form. That is, the decryptor, the D/A converter and the decoder (including an expansion decoder when data has been subjected to compressed encoding) are formed integrally and the decrypted data or decoded original digital data cannot be taken out from any intermediate stage. However, with general-purpose computers in which data is transferred over a bus for processing and hence decrypted digital data is also transferred over the bus, software can be used to control the personal computer so that the decrypted digital data can be taken out of the computer through the bus, thereby allowing the digital data to be copied.
Accordingly, it is an object of the present invention to provide a digital data reproduction device which receives and decrypts encrypted digital data to reproduce the original digital data, but is arranged to prevent the digital data from being copied.
According to the present invention there is provided a digital recording/reproduction system comprising a transmit device for sending encrypted data; a receive device for receiving and decrypting the encrypted data sent from the transmit device and outputting decrypted data; and connection means for connecting the transmit device and the receive device together by means of an interface that conforms to an established standard with which a dedicated audiovisual digital device and a general-purpose digital device are compatible, in which the receive device comprises receiving interface means that has a different configuration depending on whether the receive device is the dedicated audio-visual digital device or the general-purpose digital device.
According to the present invention there is provided a recording/reproducing method for a digital recording/reproduction system comprising a transmit device for sending encrypted data; a receive device for receiving and decrypting the encrypted data sent from the transmit device and outputting decrypted data; and connection means for connecting the transmit device and the receive device together by means of an interface that conforms to an established standard with which a dedicated audio-visual digital device and a general-purpose digital device are compatible, in which the receive device comprises receiving interface means that has a different configuration depending on whether the receive device is the dedicated audio-visual digital device or the general-purpose digital device, the method allowing proper data transmission between the transmit device and the receive device only when the receiving interface means is mounted in the corresponding digital device.
According to the present invention there is provided a semiconductor receiver device used for a receive device which is connected with a transmit device that transmits encrypted data over connection means based on a predetermined interface and decrypts the encrypted data sent from the transmit device over the connection means, the predetermined interface conforming to an established standard with which a dedicated audio-visual digital device and a general-purpose digital device comprising a computer comprising a software-controllable bus are compatible, the semiconductor receiver device comprising receiving I/F means comprising a different configuration according to whether the receive device corresponds to the dedicated audio-visual digital device or the general-purpose digital device.
According to the present invention there is provided a receive device connected with a transmit device which provides encrypted data, comprising a central processing unit; a bus connected to the central processing unit; a receiving unit connected to the bus and comprising interface means; and a processor unit connected to the bus and comprising decryption means for receiving encrypted data from the transmit device over the bus and decrypting the encrypted data to provide decrypted data and conversion means for converting the decrypted data into an analog signal, data transmission between the decryption means and the conversion means being made without the use of the bus.
According to the present invention there is provided another receive device connected to a transmit device which provides encrypted data, comprising interface means for receiving the encrypted data; decryption means for decrypting encrypted data received by the interface means to provide decrypted data; and conversion means for converting the decrypted data provided by the decryption means into an analog signal, in which at least the interface means and the decryption means being integrally incorporated into one semiconductor chip.
According to the present invention there is provided a digital recording/reproduction system comprising a transmit device for transmitting encrypted data; dedicated data reproduction device; a general-purpose data reproduction device comprising a computer; and connection means for connecting the transmit device to the dedicated data reproduction device or the general-purpose data reproduction device by means of a predetermined interface which conforms to an established standard with which the dedicated data reproduction device and the general-purpose data reproduction device are compatible, in which the dedicated data reproduction device comprises interface means for receiving the encrypted data; decryption means for decrypting the encrypted data received by the interface means to provide decrypted data; and conversion means for converting the decrypted data provided by the decryption means into an analog signal, at least the interface means and the decryption means are integrally incorporated into a first semiconductor chip, and the general-purpose data reproduction device comprises a central processing unit; a bus connected to the central processing unit; a receiving unit connected to the bus and comprising interface means, the receiving unit being formed of a second semiconductor chip which is not compatible with the first semiconductor chip; and a processor unit connected to the bus and comprising decryption means for receiving the encrypted data from the transmit device over the bus and decrypting the encrypted data to provide decrypted data, and conversion means for converting the decrypted data into an analog signal, data transmission between the decryption means and the conversion means being made without the use of the bus.
According to the digital data reproduction device of the present invention, data after decryption is not transferred over the bus of a personal computer, thus preventing decrypted data from being taken out of the computer for copying purposes.
Additional objects and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.
The objects and advantages of the present invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.